Over the past decade, extremists have increasingly aimed to integrate their ideologies into the center of society by changing the presentation of their narratives to appeal to a larger audience. This process is termed (strategic) mainstreaming. Although this phenomenon is not new, the factors that contribute to the mainstreaming of radical and extremist ideas have not been systematically summarized. To identify elements fostering mainstreaming dynamics, we conducted a systematic literature review of N = 143 studies. The results demonstrate that mainstreaming’s gradual and long-term nature makes it particularly difficult to operationalize, which is why it often remains a buzzword. In this article, we propose a novel conceptualization of mainstreaming, understanding it as two communicative steps (content positioning and susceptibility), and present 12 contributing factors. These factors can serve as starting points for future studies, helping to operationalize mainstreaming, empirically monitor it, and, subsequently, tackle its (long-term) effects.

中文翻译：

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主流化作为一个元过程：对激进和极端主义立场主流化因素的系统回顾和概念模型

在过去的十年中，极端分子越来越多地致力于通过改变其叙述方式来吸引更多受众，从而将其意识形态融入社会中心。这个过程被称为（战略）主流化。尽管这种现象并不新鲜，但导致激进和极端主义思想主流化的因素尚未得到系统总结。为了确定促进主流化动力的因素，我们对 N = 143 项研究进行了系统的文献综述。结果表明，主流化的渐进性和长期性使其特别难以实施，这就是为什么它仍然是一个流行词的原因。在本文中，我们提出了一种新颖的主流化概念，将其理解为两个沟通步骤（内容定位和敏感性），并提出了 12 个影响因素。这些因素可以作为未来研究的起点，帮助主流化的实施、实证监测，并随后解决其（长期）影响。